Titanium for heavy-duty repetitive drilling. The Bosch line of titanium-coated drill bits offer speed helix design for 3x faster drilling speed versus standard drill bits. Surface hardened to penetrate tough materials, including stainless steel. Drills clean, accurate holes in these thin materials (up to 1/8-Inch): sheet metal, ducts, steel, copper, brass, aluminum, plastic, Plexiglas, wood, veneers, vinyl siding, plasterboard, PVC, stainless steel and cast iron.